Abstract

Polyvesicular vitelline tumor of the ovary is an extremely rare variant of yolk sac tumor. We present a case of pure polyvesicular vitelline tumor in a 43-year-old woman. Light microscopy revealed a predominantly polyvesicular pattern embedded in mesoblastic stroma with the cysts showing two type of lining; tall columnar and cuboidal, or mesothelioid cells. The lining atypical cells showed occasional mitoses and intracytoplasmic PAS positive hyaline globules. In some areas, the cystic space contained a large amount of intraluminal hyaline material. Immunohistochemically, alpha- fetoprotein and alpha-1-antitrypsin were detected as a fine granular deposit in the cytoplasm of epithelial cells and hyaline globules. Electron microscopically, marked specialization of the vesicular lining cells suggested a differentiation toward gut structures and mature yolk sac.

• Keywords: Polyvesicular vitelline tumor;Yolk sac